Gabor patches are sinusoidal gratings, typically with a Gaussian envelope, which are frequently used as stimuli in psychological experiments. Using this page you can easily create and download high quality Gabor patches.
As with most topics, you can find out more about Gabor patches on Wikipedia.

In order to generate multiple Gabor patches at once, you can enter multiple values separated by a comma (",").
You can download generated stimuli separately or at once as a .zip file.
Please note that the script may time out if you generate too many or very large stimuli.

If you are here in the hope of training your eyesight, see this post for a critical discussion of recent claims that visual training with Gabor patches improves vision.